1. Field of the Invention
Embodiments of the present invention generally relate to semiconductor device test systems and, more specifically, to methods and apparatus for testing devices.
2. Description of the Related Art
When testing partially or fully completed semiconductor devices formed on a semiconductor substrate, such as integrated circuits and the like, a plurality of contact elements are typically brought into contact with the device to be tested—sometimes referred to as a device under test (or DUT). The contact elements are typically part of a probe card assembly or other similar device coupled to a test mechanism that provides electrical signals to terminals on the DUT in accordance with a predetermined testing protocol.
Such testing often can occur at high temperatures, for example up to about 150 degrees Celsius, which might require a preheat time for the probe card assembly to reach a steady state suitable to begin testing of the DUT. However, delays while waiting for the probe card assembly to heat up can be costly and reduce availability of the equipment for testing. Moreover, the probe card assembly may have a large mass (for example, due to stiffening members or assemblies for ensuring alignment of the probes extending from the probe card assembly), which further exacerbates this problem because a large mass takes longer to heat or cool.
In addition, in order to sufficiently and accurately contact all desired terminals of the DUT during a particular testing protocol, the contact elements disposed on the probe card assembly must be brought into contact with the terminals of the DUT and must maintain electrical connection therewith. However, variations in the temperature of components of the probe card assembly may induce forces that may cause the assembly (or components thereof) to deflect and/or move in a manner that may cause a misalignment of the contact elements sufficient to break electrical contact.
Accordingly, there is a need for an apparatus for testing semiconductor devices having increased thermal stability.